An image forming device which forms an image on a sheet has been conventionally known. An image forming device includes a photosensitive drum, an intermediate transfer belt, a primary transfer roller, and a secondary transfer roller. A toner image carried on the photosensitive drum is transferred onto the intermediate transfer belt by the primary transfer roller. Further, the toner image on the intermediate transfer belt is transferred onto a sheet by the secondary transfer roller. JP 2005-91613 A discloses a mechanism which makes the primary transfer roller contact and separate from the photosensitive drum and a mechanism which makes the secondary transfer roller contact and separate from the intermediate transfer belt. Additionally, a technique to rotatably support a secondary transfer roller in an opening/closing unit which can be opened/closed to a main body of an image forming device is also known.
In the above-described image forming device, the contact/separation mechanism of the primary transfer roller and the contact/separation mechanism of the secondary transfer roller are each provided with a dedicated driving source. This causes upsizing or cost increase of an image forming device. Additionally, with a technique having a secondary transfer roller rotatably supported in an opening/closing unit, at opening/closing of the opening/closing unit, the secondary transfer roller and the intermediate transfer belt rub against with each other in some cases.
An object of the present invention is to provide an image forming device capable of separating a transfer member from an image carrier in conjunction with moving operation of a plurality of moving members without increasing the number of driving sources.